The invention concerns a method for load relieving a test object, test rigs for load testing a test object, in particular for the execution of such a method, and a control system for a test rig.
In structural tests a load is applied to a structural element in a test. A known test rig comprises a multiplicity of hydraulic means positioned side by side, each introducing a partial load into the structural element such that it has a minimum deflection at its area close to a clamping device in which the structural element is fixed, and a maximum deflection at its area far away from the clamping device. In case of an emergency shutdown, a load distribution can appear that exceeds a load capacity of the structural element. In order to avoid this scenario, a control system is provided which ensure a synchronical relief of the hydraulic means in a same ratio. In one known method, a relief is achieved by pressure balancing both pressure chambers of each hydraulic means, whereby the hydraulic means are reset independently from each other. In another known method which is similar to the afore-mentioned method, the hydraulic means are reset by adjustable throttles such that the load ratio between the hydraulic means remains equal. In a third known method, a redundant independent device for relieving the test object is used.